Any fault is correct. Actually I think the part has a design fault, power up with a fault condition and tell me what your output does?
I have some of the older Renesas made and newer UTC ones that op the same.
I have some of the older Renesas made and newer UTC ones that op the same.
Should we be concerned about the reactive element of loudspeakers potentially exposing the FETs to voltage spikes greater than the amp's voltage rails? Has anyone modelled this?
It is always recommended to have reverse diodes from the amp output to the rails. The mosfets have drain to source body diodes that will bypass them if the drain source becomes reverse biased. These two mechanisms fully protect the mosfets switch and the amp.
So am I correct in my understanding that its recommended to have those diodes for all amps from chipamps like TDA2030 - LM3886 to solid state ?
I am not sure if these are included inside the chip, but assuming they are not, you should have them in your circuit. Note with mosfet outputs like the the IRFP240 etc you do not need these diodes because the drain body-source diode takes care of this for you.
MOST of those chip amps have the diodes. Explicitly says so in the LM1875 data sheet, and on every generation since. Early single supply stuff often didn’t have this, but those were only a handful of watts.
All IRF type mosfets have them, as do general purpose darlingtons. Be careful, as audio-specific darlingtons from Sanken do not have the diodes.
All IRF type mosfets have them, as do general purpose darlingtons. Be careful, as audio-specific darlingtons from Sanken do not have the diodes.
All power MOSFETs have body diodes, its an inherent part of the structure, not a separate device, as the substrate bonds direct to the middle pin and tab. Small signal MOSFETs don't usually have them because the substrate isn't pinned out. Darlington's rarely have extra diodes unless designed specifically for inductive switching. IGBT's don't have body diodes but commonly come packaged with a diode as they are normally used for inductive switching.
Lateral power MOSFETs are different to most in that the substrate is the source (not the drain), but they still have a diode built in the structure.
Lateral power MOSFETs are different to most in that the substrate is the source (not the drain), but they still have a diode built in the structure.
can this circuit be used for a BPA LM3886? if yes, is there any special wiring/connection required? thanks
The value of C1=47uF and R3=100K, determines the delay time. With these current values, the delay time is aprox. 3 seconds, and can be reduced by reducing the value of the capacitor C1 or decreasing the value of R3, and can be increased by increasing the value of C1 or increasing the value of R3.
to get 5 second delay, change the value of C1 to 47uf, R3=100K
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Should be ok. The upc1237 takes the AC mains and uses that as a trigger for power on or off. When you power up and it detects the AC, there is a delay (typically you set this at about 3-5 seconds) before the speaker relay is turned on. When powering down, as soon as the AC is removed, it immediately turns the speaker relay off. Added to this are the DC offset function (around +-1V will trigger it) and a separate input you can use for a current overload trip.
If you are using an SMPS to power your amp, you will have to arrange an AC detect input.
You can use metal film or carbon film - both will work ok.
@VIPINSAINI20
An amp that I'm building needs at least 6 seconds for DC conditions to settle.
Could you list up C1 and R3 values?
for 5 sec delay: C1 to 47uf, R3 value no need to change
for 6 sec delay :
for 7 sec delay :
for 8 sec delay :
for 9 sec delay :
for 10 sec delay :
An amp that I'm building needs at least 6 seconds for DC conditions to settle.
Could you list up C1 and R3 values?
for 5 sec delay: C1 to 47uf, R3 value no need to change
for 6 sec delay :
for 7 sec delay :
for 8 sec delay :
for 9 sec delay :
for 10 sec delay :
I like to apologize to all, earlier I made a mistake, the values for 5 seconds delay needs to be C1=47uF and R3=100K,
like wise, for 3 seconds C1=33uF and R3=100K
and like wise for approx 6 seconds valuse needs to be C1=100uF and R3=60K, again I'm sorry for my gross negligence
for approx 5 sec delay: C1 to 47uf, R3=100K
for approx 6 sec delay :C1=60uF/R3=100K
for approx 7 sec delay :C1=68uF/R3=100K
for approx 8 sec delay :C1=100uF/R3=80K
for approx 9 sec delay :C1=100uF/R3=90K
for approx 10 sec delay : C1=100uF/R3=100K
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I tested both transformer and SMPS supplies , In my case AC-Detect works in SMPS too, I connected the AC-Detect link to secondary side Diode/bridge rectifier's AC input, and AC-Detect worked like it supposed to, same as normal transformer bridge rectifier power supplies.
2 questions please (just tested the amp and ready to introduce the speaker protection into the mix)
1. if I'm not using overcurrent protection, J1 is shorted. correct? (just confirming my understanding of the PDF)
2. where do I connect the AC Detect input? Is it connected to line or neutral of the AC input? (perhaps it does not matter?)
Thanks a lot!
1. if I'm not using overcurrent protection, J1 is shorted. correct? (just confirming my understanding of the PDF)
2. where do I connect the AC Detect input? Is it connected to line or neutral of the AC input? (perhaps it does not matter?)
Thanks a lot!
so the I've wired the PCB to my power supply (+/- 37V without load) +amplifier circuit but...
- no sound is coming out from the speakers
- The LED is not turning on.
- I checked the connections/solder points and nothing seems to be wrong.
- I checked for continuity on the VOM127 part and no issues with its pins connecting to neighboring part.